Ensure window border icons repaint when DWM is enabled

ui/views/win/hwnd_message_handler.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <tchar.h>
@@ skipping 2620 matching lines @@
 
         if (delegate_->GetFrameMode() == FrameMode::CUSTOM_DRAWN) {
           DefWindowProcWithRedrawLock(WM_NCLBUTTONDOWN, HTCAPTION, l_param);
         } else {
           DefWindowProc(hwnd(), WM_NCLBUTTONDOWN, HTCAPTION, l_param);
         }
       }
       break;
     }
 
-    case WM_NCMOUSELEAVE:
+    case WM_NCMOUSELEAVE: {
+      // If the DWM is rendering the window controls, we need to give the DWM's
+      // default window procedure the chance to repaint the window border icons
+      if (HasSystemFrame())
+        handled = DwmDefWindowProc(hwnd(), WM_NCMOUSELEAVE, 0, 0, NULL) != 0;
       break;
+    }
 
     default:
       left_button_down_on_caption_ = false;
       break;
   }
   return handled;
 }
 
 void HWNDMessageHandler::SetBoundsInternal(const gfx::Rect& bounds_in_pixels,
                                            bool force_size_changed) {
@@ skipping 38 matching lines @@
   MONITORINFO monitor_info = {sizeof(monitor_info)};
   GetMonitorInfo(MonitorFromWindow(hwnd(), MONITOR_DEFAULTTOPRIMARY),
                  &monitor_info);
   gfx::Rect shrunk_rect(monitor_info.rcMonitor);
   shrunk_rect.set_height(shrunk_rect.height() - 1);
   background_fullscreen_hack_ = true;
   SetBoundsInternal(shrunk_rect, false);
 }
 
 }  // namespace views